This invention relates to an automatic oil-water separating device adapted to be used in oil-water separating tanks. Illustrative of such tanks is that disclosed in copending application filed June 11, 1973 by Stirling W. Pelton and William M. Lynch for Container Structure having a Ser. No. 368,850 now U.S. Pat. No. 3,904,524 issued Sept. 9, 1975. These tanks are normally installed underground for receiving an oil-water mixture collected from spillage areas usually associated with oil storage depots and refinery areas. The oil mixture flows to a separating chamber within the tank at which time the oil, being lighter than water, floats to and collects on the surface of the water with the latter flowing on through the tank and being subsequently discharged.
Various devices for skimming the oil from the surface of the water have been utilized in the prior art. One such device is disclosed in the copending patent application referred to above.
However, such devices do not necessarily incorporate the desirable features of the oil-water skimming device disclosed herein. These desirable features include:
1. a floatation unit which continuously adjusts the separating trough to the water level even under surge conditions; PA1 2. a unit with high efficiency, having the ability to maintain the amount of oil upon the water at a very low level and which begins its separating function upon the slightest build-up of oil; and PA1 3. a unit which is capable of rapidly restoring itself to a separating position in the event it is accidently submerged underneath the water.